Validation of the Prognostic Kidney Donor Risk Index Scoring System of Deceased Donors for Renal Transplantation in the Netherlands

Kidney Donor Risk Index and Cardiovascular Complications in a Long-Term Follow-Up Observation

Background: The suitability of the Kidney Donor Risk Index (KDRI) has not been fully validated in the European population. The aim of this study was to evaluate the value of the KDRI in predicting kidney graft function and cardiovascular events (CVEs) in a Polish cohort of kidney transplant recipients (KTRs). Methods: In this retrospective study kidney graft function and CVEs were analyzed among 1420 patients transplanted between 1999 and 2017 and followed until 2021. The KDRI was calculated according to the formula proposed by Rao. Patients were assigned into quartiles (Qs) of KDRI values. Results: Patients in Q4 were older, with higher BMI, longer cold ischemia time (CIT), and a greater rate of ischemic heart disease at the transplantation. The KDRI value determined both early and long-term graft function. During a median follow-up period of 91 months, at least one cardiovascular event was noted in 227 (16.0%) kidney transplant recipients. There was a significant increasing trend for the occurrence of post-transplant CV complications along the consecutive KDRI quartiles (χ2 = 7.3; p < 0.01) among kidney transplant patients younger than 50 years at the time of transplantation. Conclusions: The KDRI is an adequate prognostic tool also for the European population. Despite the KDRI not being used for allocation in Poland we found that kidneys with a higher KDRI are allocated to recipients with worse survival prognosis. The quality of kidneys from a deceased donor may be related to the occurrence of post-transplant cardiovascular complications in recipients younger than 50 years at the transplantation, including those without history of comorbidities such as diabetes or cardiovascular disease.

A first-in-human study of quantitative ultrasound to assess transplant kidney fibrosis

Kidney transplantation is the optimal treatment for renal failure. In the United States, a biopsy at the time of organ procurement is often used to assess kidney quality to decide whether it should be used for transplant. This assessment is focused on renal fibrotic burden, because fibrosis is an important measure of irreversible kidney injury. Unfortunately, biopsy at the time of transplant is plagued by problems, including bleeding risk, inaccuracies introduced by sampling bias and rapid sample preparation, and the need for round-the-clock pathology expertise. We developed a quantitative algorithm, called renal H-scan, that can be added to standard ultrasound workflows to quickly and noninvasively measure renal fibrotic burden in preclinical animal models and human transplant kidneys. Furthermore, we provide evidence that biopsy-based fibrosis estimates, because of their highly localized nature, are inaccurate measures of whole-kidney fibrotic burden and do not associate with kidney function post-transplant. In contrast, we show that whole-kidney H-scan fibrosis estimates associate closely with post-transplant renal function. Taken together, our data suggest that the addition of H-scan to standard ultrasound workflows could provide a safe, rapid and easy-to-perform method for accurate quantification of transplant kidney fibrotic burden, and thus better prediction of post-transplant renal outcomes.

Assessment of the Effect of Brain Death Etiologies on Organs Transplanted Per Donor

OBJECTIVES

We assessed effects of brain death etiology on organ donation, particularly focusing on the number of organs transplanted per donor.

MATERIALS AND METHODS

We evaluated 934 actual donors from 982 brain death cases at our center from April 2016 to July 2023. We analyzed donor cause of death, donor age, sex, blood group, time to consent, and hospital characteristics.

RESULTS

Among 934 actual brain death donors (63.6% male), mean age was 41.44 years. Cause of death was nontraumatic intracranial hemorrhage in 43.3% of cases, followed by trauma, hypoxia, cerebrovascular accident, toxicity, and brain tumor, respectively. Kidney, liver, heart, and lung donations occurred in 696 cases (74.5%), 809 (86.6%), 146 (15.6%), and 25 (3.4%), respectively. Donor cause of death significantly affected kidney donation (P < .001), with highest rates in trauma (83.7%), followed by brain tumors. Although cause of death did not affect liver transplant rates (P = .26), the highest rate was associated with trauma (89.9%), followed by toxicity. Difference in heart transplant rates among different causes of death was significant (P < .001), with highest rates in trauma cases. Similar to liver transplant, lung transplant was similar among different causes of death (P = .3). Organs transplanted per donor averaged 2.52 ± 1.13, with highest numbers associated with trauma (2.88 ± 1.07), followed by drug toxicity, brain tumors, hypoxia, nontraumatic intracranial hemorrhage, and cerebrovascular accident (P < .001). Compared with trauma, differences in organs transplanted per donor were significant for nontraumatic intracranial hemorrhage (mean difference 0.56; 95% CI, 0.39-0.74; P < .001), cerebrovascular accident (mean difference 0.58; 95% CI, 0.29-0.87; P < .001), and hypoxia (mean difference 0.50; 95% CI, 0.26-0.76; P = .002).

CONCLUSIONS

Understanding how cause of death influences donation can help improve organ donation practices and potentially increase the number of organs available for transplant.

Evaluation of deceased-donor kidney offers: development and validation of novel data driven and expert based prediction models for early transplant outcomes

In the face of growing transplant waitlists and aging donors, sound pre-transplant evaluation of organ offers is paramount. However, many transplant centres lack clear criteria on organ acceptance. Often, previous scores for donor characterisation have not been validated for the Eurotransplant population and are not established to support graft acceptance decisions. Here, we investigated 1353 kidney transplantations at three different German centres to develop and validate novel statistical models for the prediction of early adverse graft outcome (EAO), defined as graft loss or CKD ≥4 within three months. The predictive models use generalised estimating equations (GEE) accounting for potential correlations between paired grafts from the same donor. Discriminative accuracy and calibration were determined via internal and external validation in the development (935 recipients, 309 events) and validation cohort (418 recipients, 162 events) respectively. The expert model is based on predictor ratings by senior transplant nephrologists, while for the data-driven model variables were selected via high-dimensional lasso generalised estimating equations (LassoGee). Both models show moderate discrimination for EAO (C-statistic expert model: 0,699, data-driven model 0,698) with good calibration. In summary, we developed novel statistical models that represent current clinical consensus and are tailored to the older deceased donor population. Compared to KDRI, our described models are sparse with only four and three predictors respectively and account for paired grafts from the same donor, while maintaining a discriminative accuracy equal or better than the established KDRI-score.

A Prognostic Index for Deceased Donor Kidneys and Criteria for Identifying Suitable Candidates for Kidney Transplantation from Expanded Criteria Donors with Prolonged Waiting Times

Introduction

The kidney donor profile index (KDPI) is a valuable prognostic tool in deceased donor kidney transplantation (DDKT), while its optimization for each country using local data is essential. It remains unclear which patients derive survival benefits from expanded criteria donor (ECD) DDKT compared to waitlist or standard criteria donor (SCD) DDKT, particularly in the context of long waiting times. This study aimed to develop a prognostic index for donor kidneys and propose criteria to identify suitable candidates for ECD DDKT in Korea.

Methods

Two prediction models were developed using data from two cohorts based on national databases (the Korean Network for Organ Sharing and the National Health Insurance Data Sharing Service): cohort for the prediction of graft prognosis (n = 6,272) and cohort for the prediction of suitable candidates for ECD DDKT (n = 30,183).

Results

The Korean KDPI (K-KDPI) comprises five donor factors (age, height, diabetes mellitus, serum creatinine levels, and hepatitis C virus), associated with graft failure. The discriminatory ability of the K-KDPI for graft outcomes surpassed that of the US KDPI and dichotomous ECD criteria. ECD kidneys (K-KDPI ≥70%) showed worse allograft survival compared to SCD kidneys (K-KDPI <70%). Candidates aged ≥40 years, with negative panel reactive antibody, and without diabetes mellitus had a significantly lower mortality risk with ECD DDKT than with waitlist-or-SCD DDKT, making them suitable for ECD DDKT.

Conclusion

The K-KDPI and criteria for identifying suitable ECD recipients are expected to improve the quality assessment and efficient utilization of ECD kidneys in Korea with long waiting times.

Impact of deceased-donor characteristics on early graft function: outcome of kidney donor pairs accepted for transplantation

Introduction

The impact of deceased donor characteristics on kidney transplant outcomes is controversial. Correspondingly, the predictive performance of deceased donor scores remains moderate, and many transplant centers lack validated criteria for graft acceptance decisions. To better dissect donor-related risk from recipient and periprocedural variables, we analyzed outcomes of kidney donor pairs transplanted in different individuals.

Methods

This study explored (a)symmetry of early outcomes of 328 cadaveric kidney transplant recipients from 164 donor pairs transplanted at three Eurotransplant centers. The primary discriminatory factor was (a)symmetry of partner graft function, defined as early graft loss or impaired graft function [estimated glomerular filtration rate (eGFR) <30 mL/min] 3 months after transplantation. We reasoned that a relevant impact of donor factors would result in a high concordance rate of limited graft function or failure.

Results

The observed number of symmetric graft failure after transplantation was less than statistically expected (3 months: 1 versus 2, p = 0.89; and 12 months: 3 versus 5, p = 0.26). However, we found a trend toward an impaired 5-year graft survival of grafts with good function 3 months after transplantation but a failed or impaired partner graft compared to symmetrically well-functioning grafts (p = 0.09). Subsequently, we explored the impact of individual donor and recipient variables on early transplant outcomes. Generalized estimating equations after feature selection with LassoGEE bootstrap selected donor age, donor body mass index, and donor eGFR as the relevant risk factors.

Discussion

Our findings indicate that donor factors impact early outcomes in kidney transplantation but may have a limited role in long-term graft survival, once a graft has been accepted for transplantation. Utilizing donor-based clinical scores has the potential to aid clinicians in acceptance decisions, giving them an estimate of individual posttransplant outcomes. However, the ultimate decision for acceptance should rest with clinicians, who must consider the complex interplay of donor factors, as well as recipient and periprocedural characteristics.

Pancreas Transplantation Outcome Predictions-PTOP: A Risk Prediction Tool for Pancreas and Pancreas-Kidney Transplants Based on a European Cohort

Background

For patients with complicated type 1 diabetes having, for example, hypoglycemia unawareness and end-stage renal disease because of diabetic nephropathy, combined pancreas and kidney transplantation (PKT) is the therapy of choice. However, the shortage of available grafts and complex impact of risk factors call for individualized, impartial predictions of PKT and pancreas transplantation (PT) outcomes to support physicians in graft acceptance decisions.

Methods

Based on a large European cohort with 3060 PKT and PT performed between 2006 and 2021, the 3 primary patient outcomes time to patient mortality, pancreas graft loss, and kidney graft loss were visualized using Kaplan-Meier survival curves. Multivariable Cox proportional hazards models were developed for 5- and 10-y prediction of outcomes based on 26 risk factors.

Results

Risk factors associated with increased mortality included previous kidney transplants, rescue allocations, longer waiting times, and simultaneous transplants of other organs. Increased pancreas graft loss was positively associated with higher recipient body mass index and donor age and negatively associated with simultaneous transplants of kidneys and other organs. Donor age was also associated with increased kidney graft losses. The multivariable Cox models reported median C-index values were 63% for patient mortality, 62% for pancreas loss, and 55% for kidney loss.

Conclusions

This study provides an online risk tool at https://riskcalc.org/ptop for individual 5- and 10-y post-PKT and PT patient outcomes based on parameters available at the time of graft offer to support critical organ acceptance decisions and encourage external validation in independent populations.

Transplant Outcomes After Exposure of Deceased Kidney Donors to Contrast Medium

BACKGROUND

The administration of contrast medium is associated with acute kidney injury; however, the effect of exposure of a deceased organ donor to contrast medium on kidney transplant outcomes has been poorly studied.

METHODS

A retrospective analysis of all deceased kidney donors between 2011 and 2021 and their corresponding recipients in the Netherlands was conducted. Multivariable analyses were performed to assess the associations between contrast medium exposure and delayed graft function (DGF)/graft survival. Linear mixed models were used to assess the differences in mean estimated glomerular filtration rate values in recipients 1 to 6 y after transplantation.

RESULTS

In total, 2177 donors and 3638 corresponding kidney graft recipients were included. Twenty-four percent of the donors (n = 520) were exposed to contrast medium, corresponding to 23% of recipients (n = 832). DGF was observed in 36% (n = 1321) and primary nonfunction in 3% (n = 122) of recipients. DGF rates for donation after brain death (DBD) and donation after circulatory death (DCD) donors showed no significant effect of contrast medium exposure ( P  = 0.15 and P  = 0.60 for DBD and DCD donors, respectively). In multivariable analyses, contrast medium administration was not significantly associated with a higher DGF risk (odds ratio 1.06; 95% confidence interval, 0.86-1.36; P  = 0.63) nor was a significant predictor for death-censored graft failure (hazard ratio 1.01; 95% confidence interval, 0.77-1.33; P  = 0.93). Linear mixed models showed no difference in mean estimated glomerular filtration rate values in recipients 1 to 6 y posttransplantation ( P  = 0.78).

CONCLUSIONS

This study indicates that contrast medium administration in DBD and DCD donors has no negative effect on early and long-term kidney graft function.

Predicting 5-year survival after kidney transplantation in Colombia using the survival benefit estimator tool

INTRODUCTION

A complex relationship between donor and recipient characteristics influences kidney transplant (KT) success. A tool developed by Bae S. et al. (Survival Benefit Estimator, SBE) helps estimate post-KT survival. We aim to evaluate the predictive performance of the SBE tool in terms of 5-year patient survival after a kidney transplant.

METHODS

A retrospective cohort study of all deceased-donor KT recipients between January 2009 to December 2021. A descriptive analysis of clinical and sociodemographic characteristics was performed. The SBE online tool was used to calculate the predicted patient survival (PPS) and the survival benefit at five years post-KT. Comparisons between predictive vs. actual patient survival were made using quintile subgroups. Three Cox regression models were built using PPS, EPTS, and KDPI.

RESULTS

A total of 1145 recipients were evaluated. Mortality occurred in 157 patients. Patient survival was 86.2%. Predictive survival for patients if they remained on the waiting list was 70.6%. The PPS was 89.3%, which results in a survival benefit (SB) of 18.7% for our population. Actual survival rates were lower than the predicted ones across all the quintiles. In unadjusted analysis, PPS was a significant protective factor for mortality (HR 0.66), whereas EPTS (HR 8.9) and KDPI (HR 3.25) scores were significant risk factors. The discrimination of KDPI, PPS, and EPTS scores models were 0.59, 0.65, and 0.66, respectively.

CONCLUSION

SBE score overestimated actual survival rates in our sample. The discrimination power of the score was moderate, although the utility of this tool may be limited in this specific population.

The UK kidney donor risk index poorly predicts long-term transplant survival in paediatric kidney transplant recipients

Background

The UK kidney offering scheme introduced a kidney donor risk index (UK-KDRI) to improve the utility of deceased-donor kidney allocations. The UK-KDRI was derived using adult donor and recipient data. We assessed this in a paediatric cohort from the UK transplant registry.

Methods

We performed Cox survival analysis on first kidney-only deceased brain-dead transplants in paediatric (<18 years) recipients from 2000-2014. The primary outcome was death-censored allograft survival >30 days post-transplant. The main study variable was UK-KDRI derived from seven donor risk-factors, categorised into four groups (D1-low risk, D2, D3 and D4-highest risk). Follow-up ended on 31-December-2021.

Results

319/908 patients experienced transplant loss with rejection as the main cause (55%). The majority of paediatric patients received donors from D1 donors (64%). There was an increase in D2-4 donors during the study period, whilst the level of HLA mismatching improved. The KDRI was not associated with allograft failure. In multi-variate analysis, increasing recipient age [adjusted HR and 95%CI: 1.05(1.03-1.08) per-year, p<0.001], recipient minority ethnic group [1.28(1.01-1.63), p<0.05), dialysis before transplant [1.38(1.04-1.81), p<0.005], donor height [0.99 (0.98-1.00) per centimetre, p<0.05] and level of HLA mismatch [Level 3: 1.92(1.19-3.11); Level 4: 2.40(1.26-4.58) versus Level 1, p<0.01] were associated with worse outcomes. Patients with Level 1 and 2 HLA mismatches (0 DR +0/1 B mismatch) had median graft survival >17 years regardless of UK-KDRI groups. Increasing donor age was marginally associated with worse allograft survival [1.01 (1.00-1.01) per year, p=0.05].

Summary

Adult donor risk scores were not associated with long-term allograft survival in paediatric patients. The level of HLA mismatch had the most profound effect on survival. Risk models based on adult data alone may not have the same validity for paediatric patients and therefore all age-groups should be included in future risk prediction models.

The kidney failure risk equation predicts kidney failure: Validation in an Australian cohort

AIMS

Predicting progression to kidney failure for patients with chronic kidney disease is essential for patient and clinicians' management decisions, patient prognosis, and service planning. The Tangri et al Kidney Failure Risk Equation (KFRE) was developed to predict the outcome of kidney failure. The KFRE has not been independently validated in an Australian Cohort.

METHODS

Using data linkage of the Tasmanian Chronic Kidney Disease study (CKD.TASlink) and the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), we externally validated the KFRE. We validated the 4, 6, and 8-variable KFRE at both 2 and 5 years. We assessed model fit (goodness of fit), discrimination (Harell's C statistic), and calibration (observed vs predicted survival).

RESULTS

There were 18 170 in the cohort with 12 861 participants with 2 years and 8182 with 5 years outcomes. Of these 2607 people died and 285 progressed to kidney replacement therapy. The KFRE has excellent discrimination with C statistics of 0.96-0.98 at 2 years and 0.95-0.96 at 5 years. The calibration was adequate with well-performing Brier scores (0.004-0.01 at 2 years, 0.01-0.03 at 5 years) however the calibration curves, whilst adequate, indicate that predicted outcomes are systematically worse than observed.

CONCLUSION

This external validation study demonstrates the KFRE performs well in an Australian population and can be used by clinicians and service planners for individualised risk prediction.

Kidney Transplantation Outcome Predictions (KTOP): A Risk Prediction Tool for Kidney Transplants from Brain-dead Deceased Donors Based on a Large European Cohort

BACKGROUND

European kidney donation shortages mandate efficient organ allocation by optimizing the prediction of success for individual recipients.

OBJECTIVE

To develop the first European online risk tool for kidney transplant outcomes on the basis of recipient-only and recipient plus donor characteristics.

DESIGN, SETTING, AND PARTICIPANTS

We used individual recipient and donor risk factors and three outcomes (death, death with functioning graft [DWFG], and graft loss) for 32 958 transplants within the Eurotransplant kidney allocation system and the Eurotransplant senior program between January 2006 and May 2018 in eight European countries to develop and validate a risk tool.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox proportional-hazards models were used to analyze the association of risk factors with overall patient mortality, and proportional subdistribution hazard regression models for their association with graft loss and DWFG. Prediction models were developed with recipient-only and recipient-donor risk factors. Sensitivity analyses based on time-specific area under the receiver operating characteristic curve (AUC) with leave-one-country-out validation were performed and calibration plots were generated.

RESULTS AND LIMITATIONS

The 10-yr cumulative incidence rate was 37% for mortality, 12% for DWFG, and 41% for graft loss. In recipient-donor models the leading risk factors for mortality were recipient diabetes (hazard ratio [HR] 10.73), retransplantation (HR 3.08 per transplant), and recipient age (HR 1.08). Effects were similar for DWFG. For graft loss, diabetes (subdistributional HR [SHR] 1.32), increased donor age (SHR 1.02), and prolonged cold ischemia time (SHR 1.02) had increased SHRs. All p values were <0.001.

CONCLUSIONS

Previously identified risk factors for outcomes following kidney transplants allow for outcome prediction with 10-yr AUC values of up to 0.81.

PATIENT SUMMARY

Using European data, we estimated individual risks to predict the success of kidney transplants and support physicians in decision-making. An online tool is now available (https://riskcalc.org/ktop/) for predicting kidney transplant outcomes both before and after a donor has been identified.

Surgeon preimplantation macroscopic graft appraisal improves risk stratification of deceased kidney donors: a prospective study

BACKGROUND

Preimplantation scores assist with correct kidney graft allocation, but macroscopic graft features have never been evaluated in this scenario.

METHODS

We designed a graft appraisal questionnaire, assessed its reproducibility by comparing the senior and junior surgeon responses and evaluated which features can predict transplant outcomes in 202 patients transplanted from 144 donors at a tertiary center. We created new prediction models in combination with validated preimplantation scores. The primary outcome was graft loss or eGFR<30 mL/min/1.73 m² at six months and secondary outcomes were delayed graft function, early graft loss and graft function at six months.

RESULTS

Interrater correlation was very good for adherent perinephric fat (kappa=0.91) and acceptable for cortical surface roughness (kappa=0.51) and cortical color (kappa=0.47). Adherent perirenal fat (Odds ratio=4.77; 95% CI: 2.10-10.85) and surface roughness (OR=2.11, 95% CI: 1.25-3.58) were independent predictors of the primary outcome, improving the kidney donor risk index efficacy model (AUC 0.71 vs. 0.82, P≤0.001), while cortical color and adherent fat improved the Irish risk model for delayed graft function (AUC 0.76 vs. 0.82, P=0.03). We created nomograms to visually assess the risk of both endpoints.

CONCLUSIONS

Kidney graft macroscopic appraisal is reproducible between surgeons and can improve the accuracy of clinical preimplantational prediction scores.

Shared decision-making in advanced kidney disease: a scoping review

OBJECTIVES

To provide a comprehensive overview of interventions that support shared decision-making (SDM) for treatment modality decisions in advanced kidney disease (AKD). To provide summarised information on their content, use and reported results. To provide an overview of interventions currently under development or investigation.

DESIGN

The JBI methodology for scoping reviews was followed. This review conforms to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist.

DATA SOURCES

MEDLINE, Embase, Web of Science, Cochrane Library, Emcare, PsycINFO, PROSPERO and Academic Search Premier for peer-reviewed literature. Other online databases (eg, clinicaltrials.gov, OpenGrey) for grey literature.

ELIGIBILITY FOR INCLUSION

Records in English with a study population of patients >18 years of age with an estimated glomerular filtration rate <30 mL/min/1.73 m2. Records had to be on the subject of SDM, or explicitly mention that the intervention reported on could be used to support SDM for treatment modality decisions in AKD.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened and selected records for data extraction. Interventions were categorised as prognostic tools (PTs), educational programmes (EPs), patient decision aids (PtDAs) or multicomponent initiatives (MIs). Interventions were subsequently categorised based on the decisions they were developed to support.

RESULTS

One hundred forty-five interventions were identified in a total of 158 included records: 52 PTs, 51 EPs, 29 PtDAs and 13 MIs. Sixteen (n=16, 11%) were novel interventions currently under investigation. Forty-six (n=46, 35.7%) were reported to have been implemented in clinical practice. Sixty-seven (n=67, 51.9%) were evaluated for their effects on outcomes in the intended users.

CONCLUSION

There is no conclusive evidence on which intervention is the most efficacious in supporting SDM for treatment modality decisions in AKD. There is a lot of variation in selected outcomes, and the body of evidence is largely based on observational research. In addition, the effects of these interventions on SDM are under-reported.

Donor characteristics and their impact on kidney transplantation outcomes: Results from two nationwide instrumental variable analyses based on outcomes of donor kidney pairs accepted for transplantation

BACKGROUND

Donor-characteristics and donor characteristics-based decision algorithms are being progressively used in the decision process whether or not to accept an available donor kidney graft for transplantation. While this may improve outcomes, the performance characteristics of the algorithms remains moderate. To estimate the impact of donor factors of grafts accepted for transplantation on transplant outcomes, and to test whether implementation of donor-characteristics-based algorithms in clinical decision-making is justified, we applied an instrumental variable analysis to outcomes for kidney donor pairs transplanted in different individuals.

METHODS

This analysis used (dis)congruent outcomes of kidney donor pairs as an instrument and was based on national transplantation registry data for all donor kidney pairs transplanted in separate individuals in the Netherlands (1990-2018, 2,845 donor pairs), and the United Kingdom (UK, 2000-2018, 11,450 pairs). Incident early graft loss (EGL) was used as the primary discriminatory factor. It was reasoned that a scenario with a dominant impact of donor variables on transplantation outcomes would result in high concordance of EGL in both recipients, whilst dominance of asymmetrical outcomes could indicate a more complex scenario, involving an interaction of donor, procedural and recipient factors.

FINDINGS

Incidences of congruent EGL (Netherlands: 1·2%, UK: 0·7%) were slightly lower than the arithmetical (stochastic) incidences, suggesting that once a graft has been accepted for transplantation, donor factors minimally contribute to incident EGL. A long-term impact of donor factors was explored by comparing outcomes for functional grafts from donor pairs with asymmetrical vs. symmetrical outcomes. Recipient survival was similar for both groups, but a slightly compromised graft survival was observed for grafts with asymmetrical outcomes in the UK cohort: (10-years Hazard Ratio for graft loss: 1·18 [1·03-1·35] p<0·018); and 5 years eGFR (48·6 [48·3-49·0] vs. 46·0 [44·5-47·6] ml/min in the symmetrical outcome group, p<0·001).

INTERPRETATION

Our results suggest that donor factors for kidney grafts deemed acceptable for transplantation impact minimally on transplantation outcomes. A strong reliance on donor factors and/or donor-characteristics-based decision algorithms could result in unjustified rejection of grafts. Future efforts to optimize transplant outcomes should focus on a better understanding of the recipient factors underlying transplant outcomes.

FUNDING

None.

The Kidney Donor Profile Index (KDPI) Correlates With Histopathologic Findings in Post-reperfusion Baseline Biopsies and Predicts Kidney Transplant Outcome

Background

The increasing organ shortage in kidney transplantation leads to the necessity to use kidneys previously considered unsuitable for transplantation. Numerous studies illustrate the need for a better decision guidance rather than only the classification into kidneys from standard or expanded criteria donors referred to as SCD/ECD-classification. The kidney donor profile index (KDPI) exhibits a score utilizing a much higher number of donor characteristics. Moreover, graft biopsies provide an opportunity to assess organ quality.

Methods

In a single center analysis 383 kidney transplantations (277 after deceased and 106 after living donation) performed between January 1st, 2006, and December 31st, 2016, retrospectively underwent SCD/ECD and KDPI scoring. Thereby, the quality of deceased donor kidneys was assessed by using the KDPI and the living donor kidneys by using the living KDPI, in the further analysis merged as (L)KDPI. Baseline biopsies taken 10 min after the onset of reperfusion were reviewed for chronic and acute lesions. Survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards analysis within a 5-year follow-up.

Results

The (L)KDPI correlated with glomerulosclerosis (r = 0.30, p < 0.001), arteriosclerosis (r = 0.33, p < 0.001), interstitial fibrosis, and tubular atrophy (r = 0.28, p < 0.001) as well as the extent of acute tubular injury (r = 0.20, p < 0.001). The C-statistic of the (L)KDPI concerning 5-year death censored graft survival was 0.692. Around 48% of ECD-kidneys were classified as (L)KDPI<85%. In a multivariate Cox proportional hazard analysis including (preformed) panel reactive antibodies, cold ischemia time, (L)KDPI, and SCD/ECD-classification, the (L)KDPI was significantly associated with risk of graft loss (hazard ratio per 10% increase in (L)KDPI: 1.185, 95% confidence interval: 1.033–1.360, p = 0.025). Survival analysis revealed decreased death censored (p < 0.001) and non-death censored (p < 0.001) graft survival in kidneys with an increasing (L)KDPI divided into groups of <35, 35–85, and >85%, respectively.

Conclusion

With a higher granularity compared to the SCD/ECD-classification the (L)KDPI is a promising tool to judge graft quality. The correlation with chronic and acute histological lesions in post-reperfusion kidney biopsies underlines the descriptive value of the (L)KDPI. However, its prognostic value is limited and underlines the urgent need for a more precise prognostic tool adopted to European kidney transplant conditions.

Prolonged Organ Extraction Time Negatively Impacts Kidney Transplantation Outcome

Main Problem: Following cold aortic flush in a deceased organ donation procedure, kidneys never reach the intended 0–4°C and stay ischemic at around 20°C in the donor’s body until actual surgical retrieval. Therefore, organ extraction time could have a detrimental influence on kidney transplant outcome.

Materials and Methods: We analyzed the association between extraction time and kidney transplant outcome in multicenter data of 5,426 transplant procedures from the Dutch Organ Transplantation Registry (NOTR) and 15,849 transplant procedures from the United Network for Organ Sharing (UNOS).

Results: Extraction time was grouped per 10-min increment. In the NOTR database, extraction time was independently associated with graft loss [HR 1.027 (1.004–1.050); p = 0.022] and with DGF [OR 1.043 (1.021–1.066); p < 0.005]. An extraction time >80 min was associated with a 27.4% higher hazard rate of graft failure [HR 1.274 (1.080–1.502); p = 0.004] and such kidneys had 43.8% higher odds of developing DGF [OR 1.438, (1.236–1.673); p < 0.005]. In the UNOS database, increasing extraction times in DCD donors were associated with DGF [OR 1.036 (1.016–1.055); p < 0.005]. An extraction time >30 min was associated with 14.5% higher odds of developing DGF [OR 1.145 (1.063–1.233); p < 0.005].

Discussion: Prolonged kidney extraction time negatively influenced graft survival in Dutch donors and increased DGF risk in all deceased donor recipients.

Deep Learning Algorithms for the Prediction of Posttransplant Renal Function in Deceased-Donor Kidney Recipients: A Preliminary Study Based on Pretransplant Biopsy

Background

Posttransplant renal function is critically important for kidney transplant recipients. Accurate prediction of graft function would greatly help in deciding acceptance or discard of allocated kidneys.

Methods

: Whole-slide images (WSIs) of H&E-stained donor kidney biopsies at × 200 magnification between January 2015 and December 2019 were collected. The clinical characteristics of each donor and corresponding recipient were retrieved. Graft function was indexed with a stable estimated glomerular filtration rate (eGFR) and reduced graft function (RGF). We used convolutional neural network (CNN)-based models, such as EfficientNet-B5, Inception-V3, and VGG19 for the prediction of these two outcomes.

Results

In total, 219 recipients with H&E-stained slides of the donor kidneys were included for analysis [biopsies from standard criteria donor (SCD)/expanded criteria donor (ECD) was 191/28]. The results showed distinct improvements in the prediction performance of the deep learning algorithm plus the clinical characteristics model. The EfficientNet-B5 plus clinical data model showed the lowest mean absolute error (MAE) and root mean square error (RMSE). Compared with the clinical data model, the area under the receiver operating characteristic (ROC) curve (AUC) of the clinical data plus image model for eGFR classification increased from 0.69 to 0.83. In addition, the predictive performance for RGF increased from 0.66 to 0.80. Gradient-weighted class activation mappings (Grad-CAMs) showed that the models localized the areas of the tubules and interstitium near the glomeruli, which were discriminative features for RGF.

Conclusion

Our results preliminarily show that deep learning for formalin-fixed paraffin-embedded H&E-stained WSIs improves graft function prediction accuracy for deceased-donor kidney transplant recipients.

Temporal Trends in the Quality of Deceased Donor Kidneys and Kidney Transplant Outcomes in Europe: an analysis by the ERA-EDTA Registry

Background

We investigated 10-year trends in deceased donor kidney quality expressed as the kidney donor risk index (KDRI) and subsequent effects on survival outcomes in a European transplant population.

Methods

Time trends in the crude and standardized KDRI between 2005 and 2015 by recipient age, sex, diabetic status and country were examined in 24 177 adult kidney transplant recipients in seven European countries. We determined 5-year patient and graft survival probabilities and the risk of death and graft loss by transplant cohort (Cohort 1: 2005–06, Cohort 2: 2007–08, Cohort 3: 2009–10) and KDRI quintile.

Results

The median crude KDRI increased by 1.3% annually, from 1.31 [interquartile range (IQR) 1.08–1.63] in 2005 to 1.47 (IQR 1.16–1.90) in 2015. This increase, i.e. lower kidney quality, was driven predominantly by increases in donor age, hypertension and donation after circulatory death. With time, the gap between the median standardized KDRI in the youngest (18–44 years) and oldest (>65 years) recipients widened. There was no difference in the median standardized KDRI by recipient sex. The median standardized KDRI was highest in Austria, the Netherlands and the Basque Country (Spain). Within each transplant cohort, the 5-year patient and graft survival probability were higher for the lowest KDRIs. There was no difference in the patient and graft survival outcomes across transplant cohorts, however, over time the survival probabilities for the highest KDRIs improved.

Conclusions

The overall quality of deceased donor kidneys transplanted between 2005 and 2015 has decreased and varies between age groups and countries. Overall patient and graft outcomes remain unchanged.

Covariates adjustment questioned conclusions of predictive analyses: an illustration with the Kidney Donor Risk Index

OBJECTIVES

We aimed to illustrate that considering covariates can lead to meaningful interpretation of the discriminative capacities of a prognostic marker. For this, we evaluated the ability of the Kidney Donor Risk Index (KDRI) to discriminate kidney graft failure risk.

STUDY DESIGN AND SETTING

From 4114 French patients, we estimated the adjusted area under the time-dependent ROC curve by standardizing the marker and weighting the observations. By weighting the contributions, we also studied the impact of KDRI-based transplantations on the patient and graft survival.

RESULTS

The covariate-adjusted AUC varied from 55% (95% confidence interval [CI]: 51-60%) for a prognostic up to 1 year post-transplantation to 56% (95% CI: 52-59%) up to 7 years. The Restricted Mean Survival Time (RMST) was 6.44 years for high-quality graft recipients (95% CI: 6.30-6.56) and would have been 6.31 years (95% CI: 6.13-6.46) if they had medium-quality transplants. The RMST was 5.10 years for low-quality graft recipients (95% CI: 4.90-5.31) and would have been 5.52 years (95% CI: 5.17-5.83) if they had medium-quality transplants.

CONCLUSION

We demonstrated that the KDRI discriminative capacities were mainly explained by the recipient characteristics. We also showed that counterfactual estimations, often used in causal studies, are also interesting in predictive studies, especially regarding the new available methods.

Comprehensive assessment of deceased donor kidneys with clinical characteristics, pre-implant biopsy histopathology and hypothermic mechanical perfusion parameters is highly predictive of delayed graft function

Background: Due to the current high demand for transplant tissue, an increasing proportion of kidney donors are considered extended criteria donors, which results in a higher incidence of delayed graft function (DGF) in organ recipients. Therefore, it is important to fully investigate the risk factors of DGF, and establish a prediction system to assess donor kidney quality before transplantation.Methods: A total of 333 donation after cardiac death kidney transplant recipients were included in this retrospective study. Both univariate and multivariate analyses were used to analyze the risk factors of DGF occurrence. Receiver operating characteristic (ROC) curves were used to analyze the predictive value of variables on DGF posttransplant.Results: The donor clinical scores, kidney histopathologic Remuzzi scores and hypothermic mechanical perfusion (HMP) parameters (flow and resistance index) were all correlated. 46 recipients developed DGF postoperatively, with an incidence of 13.8% (46/333). Multivariate logistic regression analysis of the kidney transplants revealed that the independent risk factors of DGF occurrence post-transplantation included donor score (OR = 1.12, 95% CI 1.06-1.19, p < 0.001), Remuzzi score (OR = 1.21, 95% CI 1.02-1.43, p = 0.029) and acute tubular injury (ATI) score (OR = 4.72, 95% CI 2.32-9.60, p < 0.001). Prediction of DGF with ROC curve showed that the area under the curve was increased to 0.89 when all variables (donor score, Remuzzi score, ATI score and HMP resistance index) were considered together.Conclusions: Combination of donor clinical information, kidney pre-implant histopathology and HMP parameters provide a more accurate prediction of DGF occurrence post-transplantation than any of the measures alone.

Development and external validation study combining existing models and recent data into an up-to-date prediction model for evaluating kidneys from older deceased donors for transplantation

With a rising demand for kidney transplantation, reliable pre-transplant assessment of organ quality becomes top priority. In clinical practice, physicians are regularly in doubt whether suboptimal kidney offers from older donors should be accepted. Here, we externally validate existing prediction models in a European population of older deceased donors, and subsequently developed and externally validated an adverse outcome prediction tool. Recipients of kidney grafts from deceased donors 50 years of age and older were included from the Netherlands Organ Transplant Registry (NOTR) and United States organ transplant registry from 2006-2018. The predicted adverse outcome was a composite of graft failure, death or chronic kidney disease stage 4 plus within one year after transplantation, modelled using logistic regression. Discrimination and calibration were assessed in internal, temporal and external validation. Seven existing models were validated with the same cohorts. The NOTR development cohort contained 2510 patients and 823 events. The temporal validation within NOTR had 837 patients and the external validation used 31987 patients in the United States organ transplant registry. Discrimination of our full adverse outcome model was moderate in external validation (C-statistic 0.63), though somewhat better than discrimination of the seven existing prediction models (average C-statistic 0.57). The model's calibration was highly accurate. Thus, since existing adverse outcome kidney graft survival models performed poorly in a population of older deceased donors, novel models were developed and externally validated, with maximum achievable performance in a population of older deceased kidney donors. These models could assist transplant clinicians in deciding whether to accept a kidney from an older donor.

Validation of a survival benefit estimator tool in a cohort of European kidney transplant recipients

Pre-transplant prognostic scores help to optimize donor/recipient allocation and to minimize organ discard rates. Since most of these scores come from the US, direct application in non-US populations is not advisable. The Survival Benefit Estimator (SBE), built upon the Estimated Post-Transplant Survival (EPTS) and the Kidney Donor Profile Index (KDPI), has not been externally validated. We aimed to examine SBE in a cohort of Spanish kidney transplant recipients. We designed a retrospective cohort-based study of deceased-donor kidney transplants carried out in two different Spanish hospitals. Unadjusted and adjusted Cox models were applied for patient survival. Predictive models were compared using Harrell’s C statistics. SBE, EPTS and KDPI were independently associated with patient survival (p ≤ 0.01 in all models). Model discrimination measured with Harrell’s C statistics ranged from 0.57 (KDPI) to 0.69 (SBE) and 0.71 (EPTS). After adjustment, SBE presented similar calibration and discrimination power to that of EPTS. SBE tended to underestimate actual survival, mainly among high EPTS recipients/high KDPI donors. SBE performed acceptably well at discriminating post-transplant survival in a cohort of Spanish deceased-donor kidney transplant recipients, although its use as the main allocation guide, especially for high KDPI donors or high EPTS recipients requires further testing.

Usefulness of Kidney Donor Profile Index (KDPI) to predict graft survival in a South Brazilian Cohort

Introduction:

Kidney Donor Profile Index (KDPI) has been incorporated in the United States to improve the kidney transplant allocation system.

Objectives:

To evaluate deceased kidney donors’ profile using KDPI and compare to the previous United Network for Organ Sharing (UNOS) definition of expanded criteria donors (ECD) and assess the KDPI applicability to predict five-year graft survival and renal function in our sample.

Methods:

Retrospective cohort of 589 kidney transplants from deceased donors performed from January 2009 to May 2013 with follow-up until May 2018.

Results:

In 589 kidney transplants, 36.6% of donors were classified as ECD and 28.8% had KDPI ≥ 85%. Mean KDPI was 63.1 (95%CI: 60.8-65.3). There was an overlap of standard and ECD in KDPI between 60 and 95 and a significantly lower death-censored graft survival in KDPI ≥ 85% (78.6%); KDPI 0-20: 89.8%, KDPI 21-59: 91.6%, and KDPI 60-84: 83.0%; p = 0.006. The AUC-ROC was 0.577 (95%CI: 0.514-0.641; p = 0.027). Renal function at 5 years was significantly lower according to the incremental KDPI (p < 0.002). KDPI (HR 1.011; 95%CI 1.001-1.020; p = 0.008), donor-specific antibodies (HR 2.77; 95%CI 1.69-4.54; p < 0.001), acute rejection episode (HR 1.73; 95%CI 1.04-2.86; p = 0.034) were independent and significant risk factors for death-censored graft loss at 5 years.

Conclusion:

In our study, 36.6% were classified as ECD and 28.8% had KDPI ≥ 85%. KDPI score showed a moderate power to predict graft survival at 5 years. Renal function was significantly lower in patients with higher KDPI.

Validation of the Living Kidney Donor Profile Index in a European cohort and comparison of long-term outcomes with US results

BACKGROUND

Recently, a risk index for living donor kidney (LDK) transplantation [living kidney donor profile index (LKDPI)] was proposed to compare LDKs with each other and with deceased donor kidneys (DDKs). Until now, the LKDPI has not been validated externally.

METHODS

This long-term retrospective analysis included 1305 consecutive adult kidney transplant recipients who were transplanted 2000-16 in our centre. The Kidney Donor Profile Index (KDPI) was calculated in 889 DDKs and the LKDPI in 416 LDKs. Outcome was followed over a median of 6.5 years.

RESULTS

The median LKDPI was 17 and the median KDPI was 69, with a high proportion of donor kidneys with a very high KDPI (40% KDPI ≥ 80). Categorization of LDK into LKDPI quartiles (LKDPI -45-3, 3-17, 17-33, 33-90) revealed a significant difference in death-censored graft survival. Comparing corresponding subgroups of the LKDPI and KDPI (LKDPI/KDPI 0-20 or 20-40) showed comparable graft survival. A multivariate analysis adjusting for relevant recipient factors revealed the KDPI [hazard ratio (HR) 1.21; P < 0.001) and LKDPI (HR 1.15; P = 0.049) as significant independent predictors of graft loss. Time-to-event receiver operating characteristic analyses for graft survival demonstrated lower predictive discrimination of the LKDPI [area under the curve (AUC) 0.55] compared with the KDPI (AUC 0.66). The 10-year graft survival of LDK recipients was inferior in the USA compared with our centre (79% versus 84%).

CONCLUSIONS

These results provide external validation of the LKDPI to predict death-censored graft survival and confirm comparability of the LKDPI with the KDPI to discriminate post-transplant outcome.

Validation of the Kidney Donor Profile Index in Argentina

Kidney Donor Profile Index (KDPI), derived from donor characteristics, was developed in the United States in an effort to devise an objective means of assessing donor organ suitability based on predicted graft survival. The objective of this study is to analyze the utility of KDPI to predict renal graft survival in Argentina. We conducted a retrospective national cohort study of adult patients who received a deceased donor renal transplantation in Argentina between January 2008 and December 2017. The graft survival was estimated according to the KDPI stratified by quartiles. A Kaplan-Meier analysis was used to calculate survival. A Cox regression was performed to estimate the probability of graft loss for each quart of the KDPI adjusted by receptor variables (age, diabetes, sex, and dialysis time) and cold ischemia time. In a Kaplan-Meier analysis, the graft survival decreases as the quartile of KDPI increases. Multivariate analysis shows that the increase in KDPI quartile and recipient's characteristics-such as age ≥60 years, diabetes, and dialysis time-were related to the probability of graft loss. In conclusion, the KDPI system could provide a guide to objectively assess the quality of organs offered for transplantation in Argentina.

Disparities in Acceptance of Deceased Donor Kidneys Between the United States and France and Estimated Effects of Increased US Acceptance

IMPORTANCE

Approximately 3500 donated kidneys are discarded in the United States each year, drawing concern from Medicare and advocacy groups.

OBJECTIVE

To estimate the effects of more aggressive allograft acceptance practices on the donor pool and allograft survival for the population of US wait-listed kidney transplant candidates.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide study using validated registries from the United States and France comprising comprehensive cohorts of deceased donors with organs offered to kidney transplant centers between January 1, 2004, and December 31, 2014. Data were analyzed between September 1, 2018, and April 5, 2019.

MAIN OUTCOMES AND MEASURES

The primary outcome was kidney allograft discard. The secondary outcome was allograft failure after transplantation. We used logistic regression to model organ acceptance and discard practices in both countries. We then quantified using computer simulation models the number of kidneys discarded in the United States that a more aggressive system would have instead used for transplantation. Finally, based on actual survival data, we quantified the additional years of allograft life that a redesigned US system would have saved.

FINDINGS

In the United States, 156 089 kidneys were recovered from deceased donors between 2004 and 2014, of which 128 102 were transplanted, and 27 987 (17.9%) were discarded. In France, among the 29 984 kidneys recovered between 2004 and 2014, 27 252 were transplanted, and 2732 (9.1%, P < .001 vs United States) were discarded. The mean (SD) age of kidneys transplanted in the United States was 36.51 (17.02) years vs 50.91 (17.34) years in France (P < .001). Kidney quality showed little change in the United States over time (mean [SD] kidney donor risk index [KDRI], 1.30 [0.48] in 2004 vs 1.32 [0.46] in 2014), whereas a steadily rising KDRI in France reflected a temporal trend of more aggressive organ use (mean [SD] KDRI, 1.37 [0.47] in 2004 vs 1.74 [0.72] in 2014; P < .001). We applied the French-based allocation model to the population of US deceased donor kidneys and found that 17 435 (62%) of kidneys discarded in the United States would have instead been transplanted under the French system. We further determined that a redesigned system with more aggressive organ acceptance practices would generate an additional 132 445 allograft life-years in the United States over the 10-year observation period.

CONCLUSIONS AND RELEVANCE

Greater acceptance of kidneys from deceased donors who are older and have more comorbidities could provide major survival benefits to the population of US wait-listed patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03723668.

Assessment of the Kidney Donor Profile Index in a European cohort

Background

Recently, transplant societies have had to change their allocation policies to counter global organ shortages. However, strategies differ significantly and long-term outcomes and cross-regional applicability remain to be evaluated.

Methods

Therefore, we retrospectively analysed the Kidney Donor Profile Index (KDPI) of 987 adult kidney transplants at our centre using data from the Organ Procurement and Transplantation Network (OPTN) as a reference.

Results

In our cohort, the median KDPI was 66%, with a higher proportion of >85% KDPI kidneys compared with the US cohort (32.3% versus 9.2%). Among elderly patients (≥65 years of age), 62% received >95% KDPI kidneys, which were primarily allocated within the Eurotransplant Senior Program (ESP). After 10 years, the rate of death-censored graft survival was 70.5%. Recipients of >85% KDPI kidneys were significantly older, demonstrating higher mortality, poorer graft survival and lower estimated glomerular filtration rate. Patients receiving ≥99% KDPI kidneys had a satisfactory 5-year death-censored graft survival (72.9%). The 5-year survival rate of patients living with a functioning graft exceeded the matched OPTN data in the whole KDPI range, despite a higher proportion of elderly recipients. Multivariate analysis revealed KDPI as an independent risk factor for graft loss (hazard ratio 1.14/10%, P < 0.001), although C-statistics of 0.62 indicated limited discriminative ability for individuals.

Conclusion

The analysis demonstrated KDPI as a potentially useful tool for donor quality assessment in a European cohort. Most importantly, our analysis revealed acceptable outcomes even for very high KDPI kidneys.

Validation of the Kidney Donor Profile Index (KDPI) to assess a deceased donor's kidneys' outcome in a European cohort

The Kidney Donor Profile Index (KDPI) was introduced in the United States in 2014 to guide the decision making of clinicians with respect to accepting or declining a donated kidney. To evaluate whether the KDPI can be applied to a European cohort, we retrospectively assessed 580 adult patients who underwent renal transplantation (brain-dead donors) between January 2007 and December 2014 at our center and compared their KDPIs with their short- and long-term outcomes. This led to the observation of two associations: one between the KDPI and the estimated glomerular filtration rate at one year (1-y-eGFR) and the other between the KDPI and the death-censored allograft survival rate (both p < 0.001). Following this, the individual input factors of the KDPI were analyzed to assess their potential to evaluate the quality of a donor organ. We found that a donor’s age alone is significantly predictive in terms of 1-y-eGFR and death-censored allograft survival (both p < 0.001). Therefore, a donor’s age may serve as a simple reference for future graft function. Furthermore, we found that an organ with a low KDPI or from a young donor has an improved graft survival rate whereas kidneys with a high KDPI or from an older donor yield an inferior performance, but they are still acceptable. Therefore, we would not encourage defining a distinct KDPI cut-off in the decision-making process of accepting or declining a kidney graft.

Evaluation of donor kidneys prior to transplantation: an update of current and emerging methods

The lack of suitable kidney donor organs has led to rising numbers of patients with end stage renal disease waiting for kidney transplantation. Despite decades of clinical experience and research, no evaluation process that can reliably predict the outcome of an organ has yet been established. This review is an overview of current methods and emerging techniques in the field of donor kidney evaluation prior to transplantation. Established techniques like histological evaluation, clinical scores, and machine perfusion systems offer relatively reliable predictions of delayed graft function but are unable to consistently predict graft survival. Emerging techniques including molecular biomarkers, new imaging technologies, and normothermic machine perfusion offer innovative approaches toward a more global evaluation of an organ with better outcome prediction and possibly even identification of targets for therapeutic interventions prior to transplantation. These techniques should be studied in randomized controlled trials to determine whether they can be safely used in routine clinical practice to ultimately reduce the discard rate and improve graft outcomes.

Assessing the discrimination of the Kidney Donor Risk Index/Kidney Donor Profile Index scores for allograft failure and estimated glomerular filtration rate in Ireland's National Kidney Transplant Programme

Background

The Kidney Donor Risk Index (KDRI)/Kidney Donor Profile Index (KDPI) is relied upon for donor organ allocation in the USA, based on its association with graft failure in time-to-event models. However, the KDRI/KDPI has not been extensively evaluated in terms of predictive metrics for graft failure and allograft estimated glomerular filtration rate (eGFR) outside of the USA.

Methods

We performed a retrospective analysis of outcomes in the Irish National Kidney Transplant Service Registry for the years 2006–13. Associations of the KDRI/KDPI score with eGFR at various time points over the follow-up and ultimate graft failure were modelled.

Results

A total of 772 patients had complete data regarding KDRI/KDPI calculation and 148 of these allografts failed over the follow-up. The median and 25–75th centile for KDRI/KDPI was 51 (26–75). On repeated-measures analysis with linear mixed effects models, the KDRI/KDPI (fixed effect covariate) associated with eGFR over 5 years: eGFR = −0.25 (standard error 0.02; P < 0.001). The variability in eGFR mathematically accounted for by the KDRI/KDPI score was only 21%. The KDRI/KDPI score did not add significantly to graft failure prediction above donor age alone (categorized as > and <50 years of age) when assessed by the categorical net reclassification index.

Conclusions

In this cohort, while the KDRI/KDPI was predictive of eGFR over the follow-up, it did not provide additive discrimination above donor age alone in terms of graft failure prediction. Therefore it is unlikely to help inform decisions regarding kidney organ allocation in Ireland.

Association of Kidney Donor Risk Index with the Outcome after Kidney Transplantation in the Eurotransplant Senior Program

Background

We evaluated the Kidney Donor Risk Index (KDRI) scoring system for kidney transplantation in the Eurotransplant Senior Program (ESP) that allocates kidneys from older donors to older recipients (≥65 years).

Material/Methods

We retrospectively analyzed data of 37 kidney transplant recipients and 36 kidney donors who participated in kidney transplantation program according to the ESP at our center from January 2004 until December 2013.

Results

Mean recipient and donor age was 67.9±2.6 and 70.5±4.0 years respectively. The mean KDRI score was 1.7±0.27. Uncensored graft survival after 1 year and 5 years was 64.2% and 53.7% respectively. Subgroup analysis showed that in kidney transplantation with KDRI >1.83, graft survival was significantly reduced compared to lower KDRI subgroups. KDRI was significantly correlated with serum creatinine level at discharge (r=0.4).

Conclusions

ESP kidneys represent a group of high-risk grafts with high KDRI scores. Higher KDRI scores in ESP kidneys was associated with reduced postoperative short-term and long-term graft outcomes. KDRI might be useful in decision-making for selecting donors for ESP kidney transplantation.

Does the Kidney Donor Profile Index (KDPI) predict graft and patient survival in a Spanish population?

BACKGROUND AND OBJECTIVE

The Kidney Donor Profile Index (KDPI), together with other donor and recipient variables, can optimise the organ allocation process. This study aims to check the feasibility of the KDPI for a Spanish population and its predictive ability of graft and patient survival.

MATERIALS AND METHODS

Data from 2,734 kidney transplants carried out in Andalusia between January 2006 and December 2015 were studied. Cases were grouped by recipient age, categorised by KDPI quartile and both graft and patient survival were compared among groups.

RESULTS

The KDPI accurately discriminated optimal organs from suboptimal or marginal ones. For adult recipients (aged: 18-59years) it presents a hazard ratio of 1.013 (P<.001) for death-censored graft survival and of 1.013 (P=.007) for patient survival. For elderly recipients (aged: 60+years), KDPI presented a hazard ratio of 1.016 (P=.001) for death-censored graft survival and of 1.011 (P=.007) for patient survival. A multivariate analysis identified the KDPI, donor age, donation after circulatory death, recipient age and gender as predictive factors of graft survival.

CONCLUSIONS

The results obtained show that the KDPI makes it possible to relate the donor's characteristics with the greater or lesser survival of the graft and the patient in the Spanish population. However, due to certain limitations, a new index for Spain based on Spanish or European data should be created. In this study, some predictive factors of graft survival are identified that may serve as a first step in this path.

Propensity score-based comparison of the graft failure risk between kidney transplant recipients of standard and expanded criteria donor grafts: Toward increasing the pool of marginal donors

From a prospective and multicentric French cohort, we proposed an external validation study for the expanded criteria donor (ECD), based on 4833 kidney recipients transplanted for the first time between 2000 and 2014. We estimated the subject-specific effect from a multivariable Cox model. We confirmed a 1.75-fold (95% confidence interval [CI] 1.53-2.00, P < .0001) increase in graft failure risk if a given patient received an ECD graft compared to a graft from a donor with standard criteria (standard criteria donor [SCD]). Complementarily, we estimated the population-average effect using propensity scores. We estimated a 1.34-fold (95% CI 1.09-1.64, P = .0049) increase in graft failure risk among ECD patients receiving an ECD graft compared to receiving a SCD graft. With a 10-year follow-up, it corresponded to a decrease of 8 months of the mean time to graft failure due to ECD transplantation (95% CI 2-14 months). The population-average relative risk due to ECD transplantation and the corresponding absolute effect seem finally not so high. Regarding the increase of quality of life in transplantation, our study constitutes an argument to extend the definition of marginality by considering more grafts at high risk and thereby enlarging the pool of kidney grafts.

An Examination of the Application of the Kidney Donor Risk Index in British Columbia

Background:

The Kidney Donor Risk Index (KDRI) is a continuous measure of deceased donor kidney transplant failure risk that was derived in US patients based on 10 donor characteristics. In the United States, the KDRI is utilized to guide organ allocation and to inform clinical decisions regarding organ acceptance.

Objective:

To examine the application of the US-derived KDRI in a large Canadian province.

Patients:

All deceased donor kidney-only transplant recipients in British Columbia (BC) between 2005 and 2014.

Methods:

We examined the predictive performance of KDRI in BC transplant recipients and compared the overall performance of KDRI with donor age alone in predicting transplant failure (from all causes including death).

Results:

Donors in BC (N = 785) were older but included no black donors and few Hepatitis C virus (HCV)-positive donors compared with the original derivation cohort of the KDRI in the United States. The KDRI was moderately predictive of transplant failure (c statistic, 0.63) and had similar predictive performance to donor age alone (c statistic, 0.64).

Conclusion:

Our findings suggest that the US-derived KDRI does not improve the prediction of kidney transplant failure compared with donor age alone in a Canadian cohort and highlight the need to determine the applicability of KDRI in different regions.